Abstract: Mechanical properties of the gravelly soil of an earth-rock dam core wall directly affect its settlement deformation and structure safety. Most previous studies focus on the proportion and spatial distribution of its gravel blending, and lack consideration of the influence of different gravel shapes on the soil mechanical properties. This paper presents a numerical discrete element method (DEM) for simulating the gravelly soil of irregular-shaped particles to explore this shape influence. First, we construct a model library of three-dimensional irregular gravels based on the test data collected using 3D laser scanning technology, and suggest a three-variable shape evaluation standard to classify the particle shape characteristics. Then, we formulate a particle in-situ replacement method and use it to construct a particle flow model for gravelly soil. Finally, numerical tests of triaxial compression on different gravel shapes are carried out to investigate the mechanical properties of gravel soil. Results show that this standard is simple and effective and can identify accurately the multiple shape characteristics of irregular gravel. Gravel shape has a significant influence on the macroscopic mechanical properties of gravel soil; uniformity in blending various gravel shapes helps increase the strength of soil samples, thus suggesting a new direction for improving the gravel soil of earth-rock dam core walls.

Key words: gravelly soil, shape of gravel, triaxial test, numerical simulation, 3D laser scanning